Both agencies say they plan to publish their new recommendations this year, though they've been saying that for the last two years.

Anti-circumcision activists -- dubbed "intactivists" because they advocate leaving penises intact -- fear official endorsement could encourage more parents to subject their sons to what they consider an unethical and purely cosmetic procedure.

"That would be a disaster," said John Geisheker, executive director and general counsel for the advocacy group Doctors Opposing Circumcision. "We hope they waffle again."

Since 1999, the American Academy of Pediatrics' policy has stated that the potential medical benefits of circumcision are not enough to recommend it as a routine procedure, and parents should decide according to what's in the best interest of the child. The AAP's new policy isn't expected to recommend circumcision outright, but it's likely to give more credence to health benefits, said Dr. Doug Diekema, a member of the AAP's circumcision task force.

The CDC has not yet determined whether it will recommend circumcision as an STD-prevention strategy. The recommendations will go through a period of public comment, and parents wouldn't have to abide by them, said spokeswoman Elizabeth-Ann Chandler.

Supporting research

The studies driving the new recommendations, based on clinical trials in sub-Saharan Africa and published in recent years in the Lancet medical journal, found that circumcised men had a 60 percent lower incidence of contracting HIV from heterosexual sex than their uncircumcised peers.

Another study, published in January in the Lancet, found that women with circumcised partners were 28 percent less likely to contract the human papillomavirus (HPV), a common STD that can cause cervical cancer, than women with uncircumcised partners.

The counterargument

Critics say the HIV study results are of limited relevance to the U.S. because they don't address the most-frequently infected population in the U.S.: men who have sex with men. In addition, studies show that circumcision doesn't reduce HIV transmission to women. Besides, opponents say, adults should be preventing STDs through condom use.

"We're talking about amputating tissue from a child in order to prevent disease that adult behavior can prevent," Geisheker said.

Other considerations

Though circumcision has been linked to fewer urinary tract infections in infants and a lower risk of penile cancer in men, plus STD prevention, opponents say those purported benefits don't outweigh the risk of pain, complications or loss of sexual sensitivity.

Culture: Both sides agree that most parents circumcise their sons not for health but to conform to cultural norms, which raises ethical questions about whether parents should be able to irrevocably alter their kid's appearance.

"You're removing healthy, erogenous, highly nerve-supplied tissue from a human being who has not given his or her consent, and you're doing it for nontherapeutic reasons," Geisheker said.

Hygiene: Some parents believe that circumcising is cleaner than leaving the foreskin intact, which is "unfounded," said Mark Zaontz, clinical professor of urology at Temple University School of Medicine in Philadelphia. For babies and young boys, all an uncircumcised penis needs is external rinsing and washing, Zaontz said. A big mistake some parents make is to forcibly retract the foreskin, which can damage the glans (the head of the penis) and lead to scarring or bleeding.

Complications: They occur in fewer than 2 percent of cases when the circumcision is conducted in a sterile medical environment, and usually involve minor bleeding or infection, according to the CDC, though there are some cases of botched circumcisions.

Sexual experience: The foreskin has sensitive nerve endings, and intactivists note that one of the early reasons doctors gave for circumcising was to curb masturbation.

In some studies, men say sex is worse after circumcision, while in others they say it's better, said Diekema, an emergency room doctor at Seattle Children's Hospital. He said it's hard to measure something so subjective.

Pain, psychological effects: Both sides agree that circumcision can cause extreme pain, and that the trauma of experiencing that pain can have lasting psychological effects.

AAP policy says circumcision should only be performed with proper anesthesia or analgesics, though some practitioners, believing the old myth that newborns can't feel pain, don't use anything.

Fitting in: Ultimately, Diekema said, it's up to parents to determine what's best for their sons. With about half of boys getting circumcised and the other half not, it's become normal either way, he said.

Marne Hunter said she was at first nervous what people might say when she decided not to circumcise her two boys, especially because she is a conservative Jew and circumcision is tightly linked to Jewish identity. (Boys don't have to be circumcised to be Jewish, though most are.)

But Hunter, 34, said she'd be upset if someone removed a body part of hers for no good reason, and she didn't want to do that to her sons. She said the doctor tried to pressure her to circumcise.

"He said, 'Don't you want him to look like everyone else?'" said Hunter, of San Antonio. "And that's just one of the worst reasons. It's not like you have lots of little clones running around."

For Christan Davis, careful thinking about whether to circumcise her son led to the opposite conclusion. Her husband, who is uncircumcised, recalled locker room jokes that made him feel inferior, and she didn't want her boy to go through the same thing. Potential protection against STDs was another positive factor, she said, because kids are becoming sexually active earlier and they make mistakes.

Davis, 21, of North Richland Hills, Texas, did worry about the pain and said she "cried and cried and cried" the night her baby was circumcised. But it healed in a week, and her boy has been fine ever since.

"I think parents need to think carefully about it," Diekema said. "They need to think what it offers (the) child and what does it take away from them."

It's less frequent

Though 79 percent of U.S. adult men are circumcised, it's become an increasingly unpopular procedure. Fifty-six percent of infant boys were circumcised in 2008, down from 60 percent in 1998 and a peak of more than 80 percent in the 1960s, the most recent data from the CDC shows.

Possible reasons include the growth of the Hispanic population, which tends to not circumcise; a lack of Medicaid coverage for circumcision in some states; and online information questioning the purpose and highlighting the risks of the procedure.